1. Field of the Invention
The invention concerns a generator which is adapted for use as an interference frequency generator, including piezoelectric pillars for the conversion of mechanical pressure into electrical voltage which can be short-circuited by way of spark gaps.
2. Discussion of the Prior Art
A high-voltage generator of that kind is known in particular in the form of the so-called Marx surge voltage circuit in which firstly a number of capacitors connected in parallel are charged up and then switched in series across spark gaps in order thereby to apply a correspondingly multiplied voltage to a test path across which a flash-over possibly occurs. The high discharge current flow from the array of capacitors, which is linked to a voltage flash-over, gives rise to high-frequency emissions which as is known in turn in their environment at least adversely affect radio communications and in particular at the input side can interfere with or even destroy electronic circuits.
That effect of a powerful spark discharge is propagated as a non-lethal weapon, more specifically as a system for sustainedly interfering with or even destroying hostile communication procedures (see DER SPIEGEL, Issue July 1997, pages 53 ff, end of the third paragraph of the left-hand column on page 54).
A high-voltage interference generator of the general kind set forth is known from DE 199 59 358 A1 in the form of an RF-radiation source which is constructed on a modular basis as a series circuit, with an autonomously operating high-energy generator, wherein primary energy discontinuously feeds an antenna system by way of a voltage-boosting module and a discharge cable, in order to emit a high level of pulse output power in frequency ranges above 100 MHz. A piezoelectric generator which is acted upon by explosive can be provided for the primary energy supply and the voltage-boosting module connected on the output side of the piezoelectric generator can be embodied in the form of the Marx surge voltage circuit for the function discussed in the opening part of this specification. Pulse generation is implemented by the provision of a cable pulser in accordance with Vedenski, which depending on the respective circuitry configuration involved generates monopolar or bipolar square-wave voltage pulses, the pulse length of which is adjustable by way of the length of the high-voltage cable on the way to the emitting wide-band antenna. It will be noted that the pulse shape, due to the system involved, does not have a very steep flank and therefore is not optimum in regard to a wide-band action which is desired. Added to that is the fact that such a module chain circuit is very space-consuming and can therefore scarcely be handled, being at most suitable for stationary operation.
The situation does not involve such a non-lethal weapon effect if coded high-frequency signals are to be produced for object identification at a location at which no electrical energy is available for the generator circuit and therefore, in accordance with WO 98/36395, a primary energy transducer employing for example the piezoelectric effect is used. The electrical energy acts on a spark gap or the like non-linear element for producing a narrow-band high-frequency signal which for example can be coded by means of the reflection pattern of a surface wave filter and can then be emitted as identity information. If energy production were to give rise to considerable interference radiation, then the coding circuit which is to be powered from the piezoelectric system would of course suffer from interference in respect of its function or would even be blocked.
Even the production of a lighting flame in the case of a piezoelectric lighter in accordance with GB 1 554 332 A with its two piezoelectric pillars which are arranged in series mechanically in opposite directions but which are electrically connected in parallel and which are acted upon by a mechanical pulse by a resiliently biased hammer in order by way of a throttle to feed an externally disposed spark gap as a gas lighter have nothing to do with the problems of a high-energy interference pulse generator of a compact structure. That applies in corresponding manner to the starter spark plug, which operates on the same principle, for an internal combustion engine, with cylindrical piezoelectric elements which are disposed mechanically in series in opposite relationship but which are electrically connected in parallel, in accordance with JP 05256241 A (Abstract) for feeding a spark gap in front of an end of that arrangement, in that respect as in the case of the conventional electrical Otto-cycle engine spark plug. In the ignition device in accordance with DE 24 12 300 C3, which is controlled by a camshaft, the charge displacement produced by the piezoelectric effect is taken off at a spacing coupling member between two axially successively disposed cylindrical piezoelectric elements and passed by way of a shielded cable to the location of ignition of a fuel mixture or the like. It will be apparent that it is also not possible to derive therefrom anything in regard to optimising the function of a non-lethal weapon which is based on wide-band and high-energy, high-frequency interference radiation.